So if you do the express check in do you still have the ability to look at the room before you accept it? We're hoping to get a room in a specific area and close to friends we're traviling with. And I am guessing it is a better way to request a room in a certain location?
seeing your travel dates you may be limited as to what is availible. The time you arrive also has a great impact. At full capacity with an average stay of 10 days per person, they only turn over 35 to 45 room a day average, and (guessing) a third of those are premier rooms and suites and Jacuzzi rooms, so if you arrive after 1 pm your choices get reduced. They will try to accommodate you but it may take a day or two.
Mental note. When we did express check in last time us and the two other couple we were traveling with requested a specific block 0r area and none of us got what we requested let alone a specific room. I think it's more for their paperwork etc.